Are combustibles derived from legacy waste dumpsites opportunity or challenge?
The recent past has seen a paradigm shift in waste management policy in India, focussing extensively on the remediation of legacy waste dumpsites in the country.
Swachh Bharat Mission 2.0 (SBM 2.0) has earmarked a mammoth financial outlay of Rs 141,600 crore, with a focus on source segregation, material recovery facilities, phasing out single-use plastic, construction and demolition waste processing and remediation of all legacy dumpsites in the country.
While the mandate under SBM 2.0 looks very promising, with a commitment for substantial financial devolutions by the Union government to remediate the existing dumpsites, it also presents unique challenges.
A proper roadmap to divert the combustibles (plastics, paper, textiles, leather, wood, etc) recovered during the biomining process would be extremely critical to dumpsite remediation.
The combustible fraction constitutes about eight-20 per cent of the legacy waste in an old dumpsite. That means India has to deal with nearly 13 million-32 million tonnes of combustible materials lying in around 3,159 dumpsites in the country.
These combustible materials (typically referred to as segregated combustible fraction or SCF) are excavated as an end-product of the legacy waste dumpsite remediation process.
SCF are typically contaminated with inert material and high moisture content (more than 30 per cent), making it not so desirable for the cement factories.
As a result, many urban local bodies are struggling to find economically viable options for the disposal of recovered material, including combustibles.
Currently, the only available option is co-processing in the cement industry. Co-processing refers to the use of waste materials having high calorific value as alternative fuels or raw materials (AFR) to recover energy and material from them.
Due to the high temperature in cement kilns, different types of waste can be effectively disposed of without harmful emissions.
A variety of wastes, including industrial wastes and plastics, can be disposed of in an environmentally safe and sound manner through the technology of co-processing in cement kilns, according to the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal.
In cement kilns, different kinds of hazardous and non-hazardous wastes, including plastic wastes, get utilised as AFRs.
During the usage of plastic wastes in cement kilns as AFRs, the material and energy value present in them get fully utilised in the cement kiln. In this manner, plastic waste can replace the raw materials and fossil fuels that are conventionally utilised in kilns.
Every cement plant is required to have a separate feeding arrangement for undertaking the co-processing of AFRs. If the plant already has one on the calciner or kiln inlet, then the same can be used for plastics as well.
The feeding facility shall also be equipped with a lab to calculate the calorific value, ash content, moisture and chloride content of the materials.
It is important to note that Solid Waste Management Rules 2016 mandate industrial units to replace at least five per cent of their fuel requirement with refused derived fuel (RDF) — generated from recovered landfill waste.
Some cement industries in India are already successfully using RDF substitutes for fossil fuels. However, a limited number of cement industries accept combustible scrap fraction (SCF) recovered from dumpsites owing to the huge cost incurred in its transportation as well as poor quality.
Even if there is potential for utilisation, a lack of expensive additional critical infrastructure required for co-processing the SCF recovered from biomining is a hindrance.
One of the critical factors responsible for the limited usage of legacy combustibles in cement factories is the lack of trust in the quality of RDF.
The primary objective of cement plants is not MSW management system. Entities aim to produce cement without compromising its quality. However, the quality of RDF (recovered from biomining of legacy waste dumpsites) is typically compromised due to high moisture and ash content.
There are particular concerns for cement plants regarding high chlorine contents in RDF and inconsistent calorific values. Due to these concerns, they have to use this material by adding other alternative fuels like biomass, incurring additional costs.
Besides, the high cost of transportation is something to worry about. The transport cost for SCF/RDF up to 100 km from the cement plant shall be borne by the cement plant, according to the Central Public Health and Environmental Engineering Organisation guidelines.
However, beyond 100 km, the cement plant or urban local bodies (ULB) can bear the cost as mutually agreed upon by the parties.
On the contrary, the scenario at the ground level is different. ULBs bear the transportation cost irrespective of the distance.
In fact, the ULBs struggle to dispose of the combustibles recovered from legacy waste dumpsites in hilly and remote areas.
For instance, Leh Municipal Committee is currently remediating their legacy waste dumpsites, but the SCF recovered is waiting for its final disposal (nearly 300-400 trucks containing SCF).
Transportation cost is huge since the nearest cement co-processing units are situated in Himachal Pradesh, Bihar and Rajasthan. And many of the co-processing facilities are unwilling to accept the SCFs.
It is, therefore, imperative to create an enabling ecosystem to address the standardisation of RDF quality, price structure, transportation cost and standard documents for increasing the gainful utilisation of RDF by industries.
Energy-intensive industries other than co-processing units must redesign their infrastructure for controlling pollution and replacing fossil fuels with SCFs.
In addition, standards for RDFs need to be enhanced for their better acceptability. The Central Public Health and Environmental Engineering Organisation under the Ministry of Housing and Urban Affairs in 2018 recommended the Ministry of Environment, Forest and Climate Change to amend the Solid Waste Management Rules 2016. However, no step has been taken so far.
The disposal of RDF recovered from legacy waste dumpsites needs to be prioritised. Mechanisms are also required to help the ULBs develop standard operating procedures to enhance the RDF quality.
Besides, creating a win-win situation for both the cement factories and ULBs could make the whole endeavour of dumpsite remediation successful.
Recommendations
These are the recommendations to amend the Solid Waste Management Rules 2016 as suggested by MoHUA:
The cement plants located within 400 km of a solid waste-based RDF plant shall make necessary arrangements to utilise RDF in the following phase-wise manner at a price fixed by the state government. Such units should:
- Replace at least 6 per cent of fuel intake within one year from the date of amendment of these rules (equivalent calorific value/thermal substitution rate) by municipal solid waste-based SCF and/or RDF, subject to the availability of RDF.
- Replace at least 10 per cent of fuel intake within two years from the date of amendment of these rules (equivalent calorific value/thermal substitution rate) by Municipal Solid Waste based SCF and/or RDF, subject to the availability of RDF.
- Replace at least 15 per cent of its fuel intake within three years from the date of amendment of these rules (equivalent calorific value/Thermal Substitution Rate) by Municipal Solid Waste based SCF and/or RDF, subject to the availability of RDF.
- The transport cost for SCF/RDF up to 100 km from the cement plant shall be borne by the cement plant; however, beyond 100 km cement plant can transport at its own cost or by ULBs as mutually agreed upon by the parties.